False twister having radially clamping grips

ABSTRACT

A rotatable yarn gripping device for resiliently clamping a spun yarn while permitting its movement axially through a central aperture provided with a plurality of flexible filaments fixed therein, the device having improved means for providing additional resilient and damping characteristics to the flexible filaments.

United States Patent [72] Inventors Claude Guignard [Sl] Int. Cl D0lh 7/92 Ferny-Voltaire. Fr nce: 50] Field of Search 57/59, 60, Jean Pellaton, Chatelaine; Maurice Poull, 77.3, 77.45, 51.6 Meyrin, both ol, Switzerland [2]] Appl. No. 882,952 [56] References Cited 221 Filed Dec. 8. 1969 UNITED STATES PATENTS I451 F 8-1971 733,299 7/1903 Sui 57/59 [731 3,372,537 3/1968 Poull et al 57/77.3x

Columbus, Ohio [32] Priority Jan. 14, 1969 Primary Examiner-.Iohn Petrakes 33 Switzerland Attorneys-John R. Bronaugh, George R. Powers and Floyd S. [3 l 1 416/69 Levison ABSTRACT: A rotatable yarn gripping device for resiliently [54] TWISTER HAVING RADIALLY CLAMPING clamping a spun yarn while permitting its movement axially l 6 Cl 13 D through a central aperture provided with a plurality of flexible Elms "wing filaments fixed therein, the device having improved means for [52] US. Cl 57/773, providing additional resilient and damping characteristics to 57/774 the flexible filaments.

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FIG. 1

FIG. 7

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PATENTEUJUN sum 3,5 3,144

sum 2 0F 3 PATENTED Jun 8 1911 SHEET 3 BF 3 FIG. 40

FIG. 3

Fla. 8

FIG. 4

FALSE TWISTER HAVING I RADIALLY CLAMPING GI'tII-S BACKGROUND This invention pertains to radially clamping grips such as that disclosed in U.S. Pat. No. 3,372,537, issued Mar. I2, 1968, to M. Poul], et al., for radially clamping grips, wherein a length of yarn may be secured angularly by the compressive force of a plurality of flexible filaments while sliding axially during rotation. Grips of this type have found a variety of uses, particularly in textile machines for spinning and twisting yarn as disclosed in U.S. Pat. No. 3,411,284, issued Nov. 19, 1968 to A. Corbaz, et al., for Method and Apparatus for Spinning Textile Fibers.

In the first. abovestated patent, a clamping grip is shown with a plurality of flexible filaments arranged evenly around the axis of the grip, forming a bundle, with each filament at the entrance end being curved into a bow-net. The flexible filaments are adapted to exert a clamping force toward the axis of the grip and to grip the yarn angularly while permitting its passage axially. A sleeve, made of deformable material having a high elastic damping coefficient, is placed around the bundle of filaments. Where the yarn to be gripped is of the finer counts, the above arrangement may not be entirely satisfactory and the present invention pertains to means for overcoming the disadvantages of the prior art.

For a grip to maintain a clamping force upon a length of yarn, the flexible filaments must be of a diameter small enough to ensure that the space between them, when they are in contact, will be insufficient to contain the yarn. It is necessary that the flexible filaments be resiliently forced apart radially by the yarn, in order that the yarn be gripped. To avoid damaging the yarn, the pressure exerted by the filaments should be dis tributed among them as uniformly as possible. For these reasons, it is generally desirable that the diameter of each flexible filament be less than that of the yarn to be clamped. The elastic force that a flexible filament will exert decreases rapidly as the diameter of the filament is decreased. In many instances where filaments of small diameter are required the clamping forces of grips constructed as in U.S. Pat. No. 3,372,537 have been inadequate. While the damping means, such as the foam rubber sleeve of said patent, provides, in addition to the damping action, an elastic contracting force augmenting that of the flexible filaments, this augmenting force has proved to be inadequate.

SUMMARY OF THE INVENTION This invention discloses improved means to augment the resilient gripping action of small size flexible filaments in a radially clamping yarn grip.

It is the general object of the invention to provide additional strength to a rotatable grip where the clamping filaments must be of exceptionally fine wire and have inadequate strength to provide the requisite gripping force.

BRIEF DESCRIPTION OF THE DRAWING The invention will be described in greater detail by reference to specific embodiments thereof as shown in the accompanying figures ofdrawing, wherein:

FIG. II is a view in longitudinal section of the first embodiment,

FIG. In is a view in longitudinal section of a modification of the first embodiment,

FIG. 2 is an enlarged cross section taken on line ll-II in FIG.

FIG. 3 is a view in longitudinal section of the second embodiment,

FIG. 4 is an enlarged cross section taken on line IV-IV in FIG. 3,

FIG. M is a partial view in cross section ofa modification of FIG. 4,

FIG. 5 is a view in longitudinal section of the third embodiment,

FIGS. 50 and 5b are views in longitudinal section of modifications of FIG. 5,

FIG. 6 is an enlarged cross section taken on line VIVI in FIG. 5,

FIGS. 7, 8 and 9 are views in longitudinal section of modifications of the three embodiments shown in FIGS. 1, 3 and 5, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to FIGS. 1 and 2, a rotatable radial clamping grip of the general type described in said U.S. Pat. No. 3,372,537 is shown having a hollow cylindrical body I and a plurality of flexible filaments 2a to 21?, etc. These flexible filaments are distributed evenly around the axis 3 of the body I and are bent at one end so that together they form an inlet bow-net 4 of circular cross section. The central portions of the flexible filaments are parallel and form a bundle 5. Each flexible filament 2a to 2i, etc. is anchored by the end forming the inlet bow-net 4 to a crown 6 whose bore is shaped as an inlet funnel 7.

The end of each flexible filament opposite the bow-net 4 is bent radially as at Sr: ofthe flexible filament 2i so as to bear on a washer 9 that rests on the base of body 1, which base is formed with a bore 10 forming the outlet ofthe clamping grip.

FIG. 1 shows two clamping members in the form of O-ring gaskets II and I2 made from a material which has both resilient and high damping power. The gaskets I1 and 12 surround and press the filaments which form the bundle 5 against each other. The gaskets I1 and I2 are separated by a spacer I3 whose bore provides the bundle 5 with sufficient clearance to enable it to open radially when an object, such as a textile yarn, is being gripped. Annuli l4 and 15 are provided to center the O-ring gaskets and to prevent their movement in a radial direction. The annuli I4 and 15 are independent as shown in FIG. 1 but they could be combined as shoulders on the spacer 13.

In this embodiment it will be seen that it is the O-ring gaskets II and 12 which provide, on the one hand, the clamping force needed to boost the elastic forces generated by the flexible filaments 2a to 21', etc., which forces are weak when the filaments are very fine, and which ensures on the other hand damping of the radial vibrations generated by the gripped object in the bundle 5. The O-ring gaskets II and 12 must therefore be made of a material which has both resilient and damping properties.

The number of O-ring gaskets distributed along the bundle 5 can vary; instead of two as is shown in FIG. I, more than two or even a single one could be provided.

If the damping power of the O-ring gaskets II and I2 is inadequate, it is possible to replace the spacer 13 with a damping annulus I6 coaxial with O-rings II and I2 (FIG. Ia). This damping annulus I6 is made of a material having mainly damping properties, whereas the O-ring gaskets II and 12 have mainly resilient properties.

In the second embodiment, shown in FIGS. 3 and 4, the bundle 5 of flexible filaments is inserted inside deformable frames each formed by two pairs of resilient filaments disposed at right angles to one another in planes perpendicular to the axis 3 of the bundle 5. The top of the bundle is inserted into two deformable frames, one of which is formed by the pairs of resilient filaments 20a, 20b, and 21a, 21b while the other frame is formed by the pairs 22a, 22b and 23a, 23b. The resilient filaments 21a and 23a cannot be seen in FIG. 3, but filament 21a is shown in FIG. 4. The filaments of each pair, for instance, filaments 20a and 201;, have their ends embedded in a sleevelike member 24 (FIG. 4) and are disposed in positions symmetrical to one another in relation to the axis 3 of the body I. The filaments of each pair are substantially parallel, their deviation from true parallelism arising from the fact that the distance (d) between their anchorage points is slightly less than the thickness (D) of bundle 5, so that the filaments, by being prestressed in this way, apply a resilient force to the bundle 5. The other pair, comprising filaments 21a and 21b which are disposed in the same way in relation to the axis 3, lies at right angles to the pair of filaments a and 20b. These two orthogonal pairs are positioned one below the other in rubbing contact so as to form a resilient square frame enclosing the bundle 5 on all sides and exerting thereon a radially inwardly directed force. The ends of the resilient filaments are embedded in the sleevelike member 24 and may be secured in any suitable manner as by welding, adhesive bonding or force fitting.

The number of frames formed with resilient filaments can be chosen according to the amount of resilient force required to act on the bundle 5, and their distribution along the bundle 5 is arbitrary. In FIG. 3 there are four frames, two are those just explained and located near the bow-net 4. There are two other frames, formed by four pairs of resilient filaments, the pairs are numbered 25, 26, 27 and 28 (FIG. 3) and are located near the other end of the bundle 5.

To the best advantage, the resilient filaments of each pair should be in rubbing contact with the filaments of the adjacent pairs. The rubbing action, caused by the expansion and contraction of the bundle 5, provides the damping power of the device. If the damping power is insufficient, a composite device can be provided by placing around the bundle 5 one or more sleevelike members such as 29 (FIG. 3) made of deformable material having high damping power. The sleevelike members have a mainly damping action whereas the deformable frames of resilient filaments have a mainly resilient action.

If the frame of square shape formed by two pairs of resilient filaments provides insufficient resilient action, three or more pairs can be combined. With three pairs disposed at 60 to one another, a frame can be produced having a hexagonal outline. With four pairs disposed at an angle of 45, an octagonal frame can be produced as shown in FIG. 4a with four pairs of resilient filaments 30a, 30b, 31a, Mb; 32a, 32b and 33a, 33b and the bundle 5 having an object 34 such as a textile yarn gripped therein.

In the third embodiment shown in FIGS. 5 and 6, the clamping member comprises a plurality of yielding filaments which are so distributed around the bundle 5 of flexible filamerits 2a to 21', etc., as to form a resilient sheath expandable radially. At least one end of each yielding filament 40 is embedded in a stationary member in such a way that the filament may be prestressed so that the sheath may apply a radially inwardly directed force to the bundle 5. In FIG. 5, the stationary member is the crown 6, which is formed with oblique apertures 41 for receiving the ends of the yielding filaments 40. The crown 6 has a bore 42 where the arched ends of the yielding filaments may be located. When an object is engaged in the grip, any vibrations caused by its axially sliding motion are damped both by the individual yielding filaments 40 rubbing on one another and by the yielding filaments 40 rubbing on the flexible filaments of the bundle 5. lfthis damping action is inadequate, a composite device can be provided wherein the yielding filaments 40, which have a mainly resilient action, are surrounded by a sleevelike member 43 which is made of a material having a high damping power and which provides a mainly damping action.

To increase the resilient action of the clamping member without increasing the diameter of the yielding filaments 40, it is possible to embed both of their ends. As shown in FIG. 5a, the clamping member comprises a casing 44 in the base 45 of which are formed the apertures 41. A sleevelike member 43 surrounds the yielding filaments 40 and the casing 44 is fitted with a plug 46 formed with slots 47 in which the other ends of the yielding filaments 40 are secured.

In the embodiments shown in FIGS. 5 and 5a the extensible sheath surrounding the bundle 5 is formed by the straight portions of the yielding filaments 40 which lie within a meridian plane of the bundle 5. If it is desired to increase the rubbing action of the sheath on the bundle 5 and thus the damping action, the yielding filaments 400 (FIG. 5b) may be bent to give them the appearance of helix arcs. The pitch of the helixes should be large in order to permit expansion and contraction through movement of the bundle 5.

As shown by these three embodiments, the damping means comprise a clamping member adapted to assist the bundle 5 of the flexible filaments which is required to grip an object angularly. The clamping member exerts both a resilient action and a damping action. If the damping action of this clamping member is inadequate, the damping means are composite and comprise an extra element exerting a mainly damping action, such as 16, 29 and 43.

The extra element for increasing the damping action can, in all cases disclosed, be placed between the bundle 5 and the clamping member selected so that the latter can apply its resilient force through the damping element. This positioning is shown in FIGS. 7, 8 and 9 which correspond in other respects to FIGS. 1, 3 and 5 respectively. The modifications are sleeves numbered 16a, 29a and 430 which are in each case positioned between the bundle 5 and the corresponding clamping members and are made of a deformable material having high damping power.

The embodiments of the invention in which we claim an exclusive property or privilege are defined as follows:

1. A rotatable yarn-gripping device for resiliently radially clamping a yarn to cause the clamped yarn to rotate while permitting axial sliding motion of the yarn through said gripping device, said gripping device comprising:

a. a plurality of resiliently flexible filaments,

b. means supporting said filaments at one end thereof in equiangularly disposed relation about the rotation axis of said device so that each has an inwardly extending arched portion and an axially extending extension, said arched portions forming an inlet bow-net of circular cross section and said extensions forming a central bundle, said extensions being maintained in said bundle by the stress induced in said arched portions, said extensions being subjected in operation to centrifugal forces as said device rotates which centrifugal forces tend to move said extensions radially outwardly from the axis of said device and thereby release their grip upon the length of yarn therein, said extensions being further subjected individually to vibrations resulting from engagement therewith on the radially inner side thereof of projections appearing on the length of yarn as the yarn is drawn axially past said extensions through said device;

. clamping means structurally distinct from said filaments providing at least one elastic radially expansible and contractible clamp surrounding said central bundle and exerting supplemental force upon said central bundle in a band about said bundle, thereby tending to maintain said bundle contracted, the magnitude of such supplemental force and the axial extent of said band being sufficient to maintain said filaments in gripping engagement with said length of yarn as said device is rotated, and

d. damping means having a significantly greater vibration dampening effect than said clamping means, said damping means surrounding said central bundle and being operative to dampen vibration of the filaments thereof.

2. The gripping device defined in claim 1 wherein said clamping means and said damping means directly engage the exterior of said central bundle in axially spaced regions.

3. The device defined in claim 2 wherein said clamping means provides at least a pair of clamps disposed in axially spaced-apart relation along the length of said central bundle and wherein said damping means is axially interposed between the said clamps.

4. The gripping device defined in claim 1 wherein said clamping means and said damping means are disposed one within the other, whereby the effect of the exterior one of said means is operative through the interior one of said means.

5. The device defined in claim 4 wherein said clamping means is disposed interiorly of said clamping means.

6. The device defined in claim 4 wherein said clamping means is disposed exteriorly of said damping means.

7. The device defined in claim 1 wherein said clamping means is an annulus ofelastomeric material.

8. The device defined in claim 1 wherein said clamping means comprises at least two pairs of resilient filaments embedded at their ends, the resilient filaments of each individual pair being substantially parallel to one another, each of said pairs being disposed in a plane perpendicular to the axis of said bundle so that the resilient filaments of each said pair occupy symmetrical positions relative to the axis of said bundle, the said pairs of resilient filaments, by crossing one another, forming a resilient frame around said bundle and applying thereto a radial clamping force.

9. The device defined in claim 8 wherein said resilient filaments in each said pair are each in rubbing contact with at least one other filament of said pairs to provide a clamping action to said clamping means.

10. The device defined in claim 8 wherein said clamping means comprises two pairs of resilient filaments disposed at right angles to one another so that said frame formed thereby is essentially square in shape.

ll. The device as defined in claim 1 wherein said clamping means comprises a plurality of yielding filaments each of which is secured by at least one of its ends, said yielding filaments being so distributed as to form together a resilient sheath surrounding said bundle and to exert thereon a resilient radial compressive force, said yielding filaments being adapted to rub together by the expanding motion of said bundle and to impart a damping action thereto.

12. The device as defined in claim 1] wherein each one of said yielding filaments is contained in a meridian plane of said bundle.

13. The device as defined in claim 11 wherein each one of said yielding filaments is curved, at least in the portion cooperating with said bundle, in a helical arc of large pitch, said resilient sheath being twisted around the axis of said bundle.

14. A rotatable yarn-gripping device for resiliently radially clamping a yarn to cause the clamped yarn to rotate while permitting axial sliding motion of the yarn through said gripping device, said gripping device comprising:

a. a plurality of resiliently flexible filaments,

b. means supporting said filaments at one end thereof in equiangularly disposed relation about the rotation axis of said device so that each has an inwardly extending arched portion and an axially extending extension, said arched portions forming an inlet bow-net ofcircular cross section and said extensions forming a central bundle, said extensions being maintained in said bundle by the stress induced in said arched portions, said extensions being subjected in operation to centrifugal forces as said device rotates, which centrifugal forces tend to move said extensions radially outwardly from the :axis of said device and thereby release their grip upon the length of yarn therein, said extensions being further subjected individually to vibrations resulting from engagement therewith on the radially inner side thereof of projections appearing on the length of yarn as the yarn is drawn axially past said extensions through said device;

c. clamping means structurally distinct from said filaments providing at least one elastic radially expansible and contractable clamp surrounding said central bundle and exerting supplemental force upon said central bundle in a band about said bundle, thereby tending to maintain said bundle contracted, the magnitude of such supplemental force and the axial extent of said band being sufficient to maintain said filaments in gripping engagement with said length of yarn as said device is rotated; said clamping means comprising at least two pairs of resilient filaments embedded at their ends, the resilient filaments of each individual pair being substantially parallel to one another, each of said pairs being disposed in a plane perpendicular to the axis of said bundle so thatthe resilient filaments of each said pair occupy symmetrical positions relative to the axis of said bundle the said pairs of resilient filaments, by crossing one another, form a resilient frame around said bundle and apply thereto a radial clamping force.

15. The device as defined in claim 14 wherein said resilient filaments in each said pair are in rubbing contact with at least one other filament of said pair to provide a clamping action to said clamping means.

16. The device as defined in claim 14 wherein said clamping means comprises two pairs of resilient filaments disposed at right angles to one another so that said frame formed thereby is essentially square in shape.

Dedication 3,583,144.0Zaude Gm'gnawl, Ferney-Voltaire, France, and Jean Fella/ton, Chatelaine, and Maurice PouU, Mevriin Switzerland. FALSE TlVISTER HAVING RADTALLY (TAMPING GRIPS. Patent,

dated June 8, 1971. Dedication filed Mar. 23, 1977, by the assignce, E Zectrospa'n Corporation.

Hereby dedicates to the Public the entire term of said patent.

[Ofii'oial Gazette May 10, 1.977.] 

1. A rotatable yarn-gripping device for resiliently radially clamping a yarn to cause the clamped yarn to rotate while permitting axial sliding motion of the yarn through said gripping device, said gripping device comprising: a. a plurality of resiliently flexible filaments, b. means supporting said filaments at one end thereof in equiangularly disposed relation about the rotation axis of said device so that each has an inwardly extending arched portion and an axially extending extension, said arched portions forming an inlet bow-net of circular cross section and said extensions forming a central bundle, said extensions being maintained in said bundle by the stress induced in said arched portions, said extensions being subjected in operation to centrifugal forces as said device rotates which centrifugal forces tend to move said extensions radially outwardly from the axis of said device and thereby release their grip upon the length of yarn therein, said extensions being further subjected individually to vibrations resulting from engagement therewith on the radially inner side thereof of projections appearing on the length of yarn as the yarn is drawn axially past said extensions through said device; c. clamping means structurally distinct from said filaments providing at least one elastic radially expansible and contractible clamp surrounding said central bundle and exerting supplemental force upon said central bundle in a band about said bundle, thereby tending to maintain said bundle contracted, the magnitude of such supplemental force and the axial extEnt of said band being sufficient to maintain said filaments in gripping engagement with said length of yarn as said device is rotated, and d. damping means having a significantly greater vibration dampening effect than said clamping means, said damping means surrounding said central bundle and being operative to dampen vibration of the filaments thereof.
 2. The gripping device defined in claim 1 wherein said clamping means and said damping means directly engage the exterior of said central bundle in axially spaced regions.
 3. The device defined in claim 2 wherein said clamping means provides at least a pair of clamps disposed in axially spaced-apart relation along the length of said central bundle and wherein said damping means is axially interposed between the said clamps.
 4. The gripping device defined in claim 1 wherein said clamping means and said damping means are disposed one within the other, whereby the effect of the exterior one of said means is operative through the interior one of said means.
 5. The device defined in claim 4 wherein said clamping means is disposed interiorly of said damping means.
 6. The device defined in claim 4 wherein said clamping means is disposed exteriorly of said damping means.
 7. The device defined in claim 1 wherein said clamping means is an annulus of elastomeric material.
 8. The device defined in claim 1 wherein said clamping means comprises at least two pairs of resilient filaments embedded at their ends, the resilient filaments of each individual pair being substantially parallel to one another, each of said pairs being disposed in a plane perpendicular to the axis of said bundle so that the resilient filaments of each said pair occupy symmetrical positions relative to the axis of said bundle, the said pairs of resilient filaments, by crossing one another, forming a resilient frame around said bundle and applying thereto a radial clamping force.
 9. The device defined in claim 8 wherein said resilient filaments in each said pair are each in rubbing contact with at least one other filament of said pairs to provide a clamping action to said clamping means.
 10. The device defined in claim 8 wherein said clamping means comprises two pairs of resilient filaments disposed at right angles to one another so that said frame formed thereby is essentially square in shape.
 11. The device as defined in claim 1 wherein said clamping means comprises a plurality of yielding filaments each of which is secured by at least one of its ends, said yielding filaments being so distributed as to form together a resilient sheath surrounding said bundle and to exert thereon a resilient radial compressive force, said yielding filaments being adapted to rub together by the expanding motion of said bundle and to impart a damping action thereto.
 12. The device as defined in claim 11 wherein each one of said yielding filaments is contained in a meridian plane of said bundle.
 13. The device as defined in claim 11 wherein each one of said yielding filaments is curved, at least in the portion cooperating with said bundle, in a helical arc of large pitch, said resilient sheath being twisted around the axis of said bundle.
 14. A rotatable yarn-gripping device for resiliently radially clamping a yarn to cause the clamped yarn to rotate while permitting axial sliding motion of the yarn through said gripping device, said gripping device comprising: a. a plurality of resiliently flexible filaments, b. means supporting said filaments at one end thereof in equiangularly disposed relation about the rotation axis of said device so that each has an inwardly extending arched portion and an axially extending extension, said arched portions forming an inlet bow-net of circular cross section and said extensions forming a central bundle, said extensions being maintained in said bundle by the stress induced in said arched portions, said extensions being subjected in operation to centrifugal forces as said device rotates, which centRifugal forces tend to move said extensions radially outwardly from the axis of said device and thereby release their grip upon the length of yarn therein, said extensions being further subjected individually to vibrations resulting from engagement therewith on the radially inner side thereof of projections appearing on the length of yarn as the yarn is drawn axially past said extensions through said device; c. clamping means structurally distinct from said filaments providing at least one elastic radially expansible and contractable clamp surrounding said central bundle and exerting supplemental force upon said central bundle in a band about said bundle, thereby tending to maintain said bundle contracted, the magnitude of such supplemental force and the axial extent of said band being sufficient to maintain said filaments in gripping engagement with said length of yarn as said device is rotated; said clamping means comprising at least two pairs of resilient filaments embedded at their ends, the resilient filaments of each individual pair being substantially parallel to one another, each of said pairs being disposed in a plane perpendicular to the axis of said bundle so that the resilient filaments of each said pair occupy symmetrical positions relative to the axis of said bundle, the said pairs of resilient filaments, by crossing one another, form a resilient frame around said bundle and apply thereto a radial clamping force.
 15. The device as defined in claim 14 wherein said resilient filaments in each said pair are in rubbing contact with at least one other filament of said pair to provide a clamping action to said clamping means.
 16. The device as defined in claim 14 wherein said clamping means comprises two pairs of resilient filaments disposed at right angles to one another so that said frame formed thereby is essentially square in shape. 